A lamp, for example, a straight tube fluorescent lamp has two bases fixed at both ends of its lamp tube, respectively. Each of the bases has two lamp pins for power supply, projecting from its own end face in the length (axis) direction of the lamp tube. Such many kinds of lamp sockets for placing and fixing a lamp at a mounting position of a light fitting have been heretofore provided.
For example, there is a lamp socket having a socket case as well as two contacts and a rotator which are put in the case. The socket case is fixed to a body of luminaire. The two contacts can make contact with two lamp pins projecting from one end (base) of a lamp, respectively. The rotator is rotatably supported by the socket case. The socket case has a cylindrical side that is formed with a slit (fixed slit) through which the two lamp pins can pass. On the other hands, one surface of the rotator is a facing surface with a base of the lamp, and corresponds to one end face of the cylindrical socket case. The facing surface is also formed with a slit (rotary slit). Two contacts in the socket case are arranged such that the rotary slit intervenes, in the width direction of the rotary slit when the rotary slit is aligned with the fixed slit.
A procedure of attaching a lamp to luminaire having a pair of lamp sockets is explained. In each lamp socket, when the rotary slit is aligned with the fixed slit, two lamp pins are inserted into the socket case from the fixed slit along the rotary slit. The lamp is then rotated around the axis of the lamp tube (the projection direction of the lamp pins and the central axis of the base). Thereby, the two lamp pins are connected with the two contacts, respectively. At the same time, the two lamp pins are consequently unable to pass through the fixed slit. That is, the lamp is fixed to two lamp sockets, and the attachment of the lamp to the mounting position is finished. Also, if the lamp is rotated around the opposite direction when the lamp was attached, the two pairs of lamp pins can be pulled out of the fixed slits of the two lamp sockets, respectively. Therefore, the lamp can be removed from the mounting position.
Incidentally, in the above-stated lamp socket, a space for rotating a lamp at the mounting position by hand is required around the lamp. However, a structural member such as a reflector panel or the like is frequently located adjacent to a lamp at the mounting position owing to downsizing of luminaire or the like in recent years. In this instance, a sufficient space cannot be secured around the lamp, and accordingly it is difficult to rotate the lamp by hand.
On account of this, Japanese Patent Application Publication Number 2005-294239 published on Oct. 20, 2005 (hereinafter referred to as a “Patent Document 1”) discloses a lamp socket by which a lamp can be rotated even if it is not grasped. As shown in FIG. 1, the lamp socket 1 of the Patent Document 1 has an operational arm 600a unified with a rotator 600. This operational arm 600a is formed to stick out from a cylindrical side of a socket case 610. In this lamp socket, by moving the operational arm 600a to rotate the rotator 600, a lamp rotates together with a rotary slit 620 of the rotator 600. That is, a lamp can be rotated even if it is not grasped.
By the way, in the lamp socket 1 of FIG. 1, a lamp is rotated around the axis of the lamp tube when the lamp is attached or detached. Therefore, the two lamp sockets 1 can be used for a straight tube fluorescent lamp having a straight lamp tube and two bases fixed to both ends of the lamp tube. However, the lamp socket 1 cannot be used for a lamp having a non-straight lamp tube and two bases fixed to both ends of the lamp tube.